1. Field of the Invention
This invention relates generally to apparatus for inserting prewound coil and slot wedges into the slots of an internally slotted dynamoelectric machine core member. More specifically, the present invention relates to an improved simplified wedge feeding mechanism for such devices.
2. Description of the Prior Art
Apparatus for inserting prewound coil into the slots of a dynamoelectric machine stator core member is shown in U.S. Pat. No. 2,432,267, and coil inserting apparatus which also inserts slot wedges into the stator slots following insertion of the coils is further shown in U.S. Pat. Nos. 3,402,462; 3,377,690 and 3,447,225, the latter two patents being assigned to the assignee of the present application.
The wedge feeding mechanism for such apparatus typically comprises a plurality of elongated, small cross-section push rods which axially push the wedges from the wedge magazine slots into wedge guide slots and thereafter into the stator core member in a single stroke. Due to the long stroke required with such machines, and particularly with machines for inserting coil and wedges in stator core members having long stack lengths, such as stator core members for submersible pump motors, it has been necessary to provide additional means for supporting the push rods to prevent buckling thereof as shown in U.S. Pat. No. 3,377,690. Further, inasmuch as the slot wedges sometimes have a tendency to jam in the wedge guide slot or elsewhere it has also been necessary to provide overload means to sense the jamming and remove power from the push rod driving means. Needless to say, the push rod supporting means and overload means substantially contributes to the overall cost of the inserting apparatus.
In order to overcome the disadvantages of the prior art single stroke coil and wedge inserting apparatus, the two stroke coil and wedge inserting apparatus shown in U.S. Pat. No. 3,872,568, which patent is assigned to the assignee of the present application, was developed. The apparatus of this patent provides for front and rear wedge pushing elements which advance first and second groups of wedges to the stator core member and to an intermediate position, respectively, with each forward stroke of the hydraulic ram. In this patent, the front wedge pushing element consists of a plurality of fingers which are movable between radially retracted and protracted positions. On the forward stroke of the ram, the fingers on the front pushing element are radially protracted into the wedge guide slots so as to engage the wedges and move them forward to the stator core member as the front wedge pushing element is advanced by the hydraulic ram. On the retracting stroke of the hydraulic ram, the front pushing element fingers are radially retracted so that they pass under the group of wedges located at the intermediate position without engaging them.
While the coil and wedge inserting apparatus of U.S. Pat. No. 3,872,568 operates satisfactorily for its intended purpose, the intricate nature of the front pushing element requires costly labor time to produce and thus adds to the overall cost of the machine. Further, the intricate nature of the front wedge pushing element increases the chance of a costly equipment failure or that the wedge feeding mechanism might jam.